Our general objective is to determine, by means of a concurrent case-control study, whether risks of various histologic types of ovarian cancer are influenced by a) prior reproductive experience of the patient b) cancer among first degree female relatives c) a combination of these factors. The hypothesis that low fertility or infertility contribute to risk will be refined and assessed. Also, we will have a systematically derived and validated statement of familial risk among first degree female relatives. Additional study variables will include prior hormonal therapy, pre-existing medical conditions and menstrual history. In the proposed study, two population controls will be selected for each ovarian cancer patient interviewed. The controls will be matched by age and county of residence. Demographic and clinical data will be collected from hospital records of each ovarian cancer patient, and pathology slides reviewed. Various types of epidemiologic data will be collected through face to face interviews with each patient and control. Standardized follow-up procedures have been developed for verifying whether or not the relatives have ever been diagnosed or died from a malignancy.